Warning interlock system for unlocked safes

ABSTRACT

A warning interlock system which provides an audible signal when the passageway door is open to an enclosed area containing an unlocked safe. The invention incorporates the use of miniature switches in the passageway door casings and in the lock bolt recesses of safes. The miniature switch contacts are arranged so as to be closed when the corresponding passageway door and safe bolt are open. The closed contacts thus complete a first circuit causing the alarm to be energized. In another aspect of the invention, a relay is utilized in the system in order to complete a second circuit for energizing the alarm upon the loss of potential to the warning interlock system.

United States atet [72] Inventors Robert G. Dunn;

Emil J. Walk, both of Dayton, Ohio [21 Appl. No. 789,278

[22] Filed Jan. 6,1969

[45] Patented Sept. 7, 1971 [73] Assignee The United States of America as represented by the Secretary of the Air Force 54] WARNING INTERLOCK SYSTEM FOR Primary Examiner-John W. Caldwell Assistant ExaminerScott F. Partridge Attorneysl-larry A. Herbert, Jr. and Robert K. Duncan ABSTRACT: A warning interlock system which provides an audible signal when the passageway door is open to an enclosed area containing an unlocked safe. The invention incorporates the use of miniature switches in the passageway door casings and in the lock bolt recesses ofsafes. The miniature switch contacts are arranged so as to be closed when the corresponding passageway door and safe bolt are open. The closed contacts thus complete a first circuit causing the alarm to be energized. In another aspect of the invention, a relay is utilized in the system in order to complete a second circuit for energizing the alarm upon the loss of potential to the warning interlock system.

UNLOCKED SAFES 1 Claim, 2 Drawing Figs.

[52] US. Cl 340/274 [51] Int. Cl E05g 3/00, G08b 13/08 [50] Field oiSearch 340/274, 275, 276, 333; 307/66 [56] References Cited UNITED STATES PATENTS 2,064,533 12/1936 Grant, Jr. 307/66 1,102,571 7/1914 Colby 340/274 X yla '3, ,3 H I 2 r WARNING INTERLOCK SYSTEM FOR UNLOCKED SAFES BACKGROUND OF THE INVENTION This invention is directed to a warning system of the character herein described for the purpose of indicating an open safe lock bolt when a door to a room containing a monitored safe is opened. There are warning systems presently in use, however, many of the applications are restricted to safes as they are being manufactured, or if applied on existing safes would require costly structural modifications. The present invention is very inexpensive and can be incorporated on any safe, regardless of age'or manufacture, without any physical or structural modification.

SUMMARY OF THE INVENTION The invention in order to become operable requires two sources of electrical energy, an AC/DC alarm, at least two miniature pressure switches and electrical conductors of suitable gauge for connecting the system together. The first switch is positioned in the safe lock bolt recess and the second one is located on the passageway casing leading to the area where the safe is located. The first switch has contacts that are adapted to be closed when the safe lock bolt is open, the second switch has contacts that are adapted to be closed when the passageway door is open. Therefore, when both the safe lock bolt and the passageway door are open, a first circuit will be completed, thus energizing the alarm.

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a circuit diagram of the Warning Interlock System together with the relay used for sensing loss of potential.

FIG. 2 is a view of a miniature switchmounted within the safe lock bolt recess of a safe with the lock bolt partially open.

DESCRIPTION OF THE PREFERRED EMBODIMENT In the embodiment of the invention shown in FIG. 1, the power source 3 is represented by a transformer having a primary winding 1, connecting terminals 24 and 25, secondary winding 2, connecting terminals 8 and 23. The alarm 7 having first and second connecting terminals 26 and 27 where the first terminal is connected to transformer terminal 8. At 9 the alarm is serially connected to miniature switch by conductor 17 which extends from within the lock bolt recess to the alarm 7. Switch 15 is mounted by conventional means inside the safe lock bolt recess and is separated from the metallic safe body by insulating strip 16 as illustrated in FIG. 2. Switch 15 has contacts 13 and 14 which are closed when the lock bolt 12 is partially withdrawn from recess 11. Serially connected to miniature switch 15 by conductor 18, which also extends from within the recess 11, is another similarly operated miniature switch 19. Switch 19 is mounted on a passageway door casing (not shown) in the same manner that switch 15 is mounted in recess 11. Contacts 20 and 21 of switch 19 are closed when the passageway door (not shown) is open. Connected to contact 21 is conductor 22 which is the return to the transformer secondary. FIG. 1 further illustrates the fact that any number of safes or passageway doors can be included in the system. If there are an N number of safes, an N number of switches will be required, one mounted in each safe lock bolt recess. If there are an N number of passageway doors, an N number of switches will be required, one for each passageway. Of course, it must be kept in mind that the switches 15 and N must be parallel to each other and in series with the alarm. The conductors 17 and 18 which extend from within the recess 11 must be of a size that does not hinder the lock bolt or safe door from closing completely.

It can thus be that a safe housing a switch 15 will, under the condition of a safe lock bolt partially displaced from the safe lock bolt recess, have contacts 13 and 14 made thus completing the circuit up to the passageway casing upon which switch 19 is mounted. Upon the opening of the passageway door, contacts 20 and 21 will be made therefore completing a first circuit energizing alarm 7.

A relay 4 is connected across the primary terminal connections 24 and 25. Relay contact 6 is connected to alarm 7 through battery 10 and the hinged ends of the relay is connected to terminal 8. In the event' of a loss ofpotential, relay 4 will be deenergized resulting in contact6 being made through hinged contact 5. A second circuit is thus formed causing alarm 7 to be energized by the battery source 10. It can be seen that whenever the alarm is energized, the safe-custodian will have notice that the Warning lnterlock System is incapable of monitoring for an unlocked safe lock bolt condition or that someone has opened a door to a room containing an unlocked safe. It will be necessary for the safe custodian to investigate in order to determine what condition has actually occurred. It can be seen that battery voltage will not be superimposed on the system as long as transformer 3 remains energized because of the open relay contact.

If desired, two alarms, each having its own unique audible signal could be used. One for the open safe lock bolt condition, and the other for loss of potential. Under this type of operation, the safe custodian will immediately know what has caused the energization of the alarm.

We claim: a

l. A warning interlock system for unlocked safes comprising, in combination:

A. an electrically powered audible alarm having a first and a second connecting terminal;

B. a power transformer having a primary and a secondary winding, each winding having first and second connecting terminals, with the first terminal of the secondary winding electrically connected to the first connecting alarm ter-- minal;

C. a first and a second miniature pressure operated switch serially connected to each other and electrically connecting the second alarm terminal through said switches to the second connecting terminal of the secondary winding when both of the switches are closed;

D. said first miniature pressure operated switch mounted in a recess which is to be occupied by a safe lock bolt where said first switch is closed upon displacement of the lock bolt from the fully locked position within the safe lock bolt recess;

B. said second switch mounted on a passageway door casing of the enclosed area, said second switch adapted to be closed whenever said passageway door is not fully closed thus providing a closed circuit from the first terminal of the secondary winding to;the first terminal of the alarm and from the second terminal of the alarm through the first and second switches to the second terminal of the secondary winding whenever neither the safe lock bolt nor passageway door is fully closed whereby the alarm will be enei'gized whenever neither the safe lock bolt nor passageway door is fully closed and potential is supplied to the transformer; and- F. means for energizing the alarm whenever there is a loss of potential to the transformer, said means comprising:

1. a relay having an energization winding and a switch with first and second connecting terminals, said switch being held open when the energization winding is energized and closed when the energization winding is not energized;

. a battery, one terminal of which is connected to one connecting terminal of said alarm and the other terminal of which is connected to the first connecting terminal of said relay switch, the second connecting relay switch terminal being connected to the other connecting terminal of said alarm; and

. the energization winding of the relay connected to the first and second terminals of the primary winding of the power transformer, whereby the energization winding will be energized when potential is supplied to the plied to the power transformer whereby the battery will operate the alarm. 

1. A warning interlock system for unlocked safes comprising, in combination: A. an electrically powered audible alarm having a first and a second connecting terminal; B. a power transformer having a primary and a secondary winding, each winding having first and second connecting terminals, with the first terminal of the secondary winding electrically connected to the first connecting alarm terminal; C. a first and a second miniature pressure operated switch serially connected to each other and electrically connecting the second alarm terminal through said switches to the second connecting terminal of the secondary winding when both of the switches are closed; D. said first miniature pressure operated switch mounted in a recess which is to be occupied by a safe lock bolt where said first switch is closed upon displacement of the lock bolt from the fully locked position within the safe lock bolt recess; E. said second switch mounted on a passageway door casing of the enclosed area, said second switch adapted to be closed whenever said passageway door is not fully closed thus providing a closed circuit from the first terminal of the secondary winding to the first terminal of the alarm and from the second terminal of the alarm through the first and second switches to the second terminal of the sEcondary winding whenever neither the safe lock bolt nor passageway door is fully closed whereby the alarm will be energized whenever neither the safe lock bolt nor passageway door is fully closed and potential is supplied to the transformer; and F. means for energizing the alarm whenever there is a loss of potential to the transformer, said means comprising:
 1. a relay having an energization winding and a switch with first and second connecting terminals, said switch being held open when the energization winding is energized and closed when the energization winding is not energized;
 2. a battery, one terminal of which is connected to one connecting terminal of said alarm and the other terminal of which is connected to the first connecting terminal of said relay switch, the second connecting relay switch terminal being connected to the other connecting terminal of said alarm; and
 3. the energization winding of the relay connected to the first and second terminals of the primary winding of the power transformer, whereby the energization winding will be energized when potential is supplied to the power transformer, thus preventing the battery from operating the alarm, and whereby the energization winding will not be energized when potential is not supplied to the power transformer whereby the battery will operate the alarm.
 2. a battery, one terminal of which is connected to one connecting terminal of said alarm and the other terminal of which is connected to the first connecting terminal of said relay switch, the second connecting relay switch terminal being connected to the other connecting terminal of said alarm; and
 3. the energization winding of the relay connected to the first and second terminals of the primary winding of the power transformer, whereby the energization winding will be energized when potential is supplied to the power transformer, thus preventing the battery from operating the alarm, and whereby the energization winding will not be energized when potential is not supplied to the power transformer whereby the battery will operate the alarm. 